   "Returns the ffmpeg options for encoding / copying the aac audio
   stream."
   [audio-streams index codec]
-  (let [audio (audio-to-encode audio-streams)
+  (let [audio (audio-to-encode audio-streams codec)
         exists (= (:codec_name audio) codec)]
     (conj ["-map" (str "0:" (:index audio))
            (str "-c:a:" index) (if exists "copy" codec)]

  streams."
  [{:keys [audio-streams]}]
  (into (audio-encoder-options audio-streams 0 "aac")
        (when-let [audio (audio-to-encode audio-streams)]
          (when (> (:channels audio) 2)
            (audio-encoder-options audio-streams 1 "ac3")))))



(defn audio-to-encode
  "Returns the best audio stream to use for the target codec."
  [audio-streams codec]
  (let [audio (reverse (sort-by #(parse-long (:bit_rate %)) audio-streams))]
    (or (first (filter #(= (-> % :codec_name) codec) audio))
        (first (filter #(= (-> % :disposition :default) 1) audio))
        (first audio))))

(defn audio-codec-options
